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SERIES IOS-521 I/O SERVER MODULE                            EIA/TIA-422B SERIAL COMMUNICATION MODULE 
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- 3 - 

 

False Start Bit Detection - 

Prevents the receiver from 

assembling false data characters due to low-going noise 
spikes on the RxD input line.

 

 

Programmable Baud Rate -

 The internal baud rate 

generator allows the 921.6K maximum baud rate to be 
divided by any divisor between 1 and 2

(16-1)

, providing 

support for all standard baud rates.

 

 

Interrupt Support -

 Individually controlled transmit empty, 

receive ready, line status, data set, & flow control interrupts 
may be generated.  Unique interrupts can be assigned to 
each port.  Interrupts use a priority shifting scheme based 
on the last interrupt serviced, preventing the continuous 
interrupts of one port from blocking the interrupts of another 
port. 

 

Socketed Termination and Bias Resistors 

- The network 

termination and bias resistors are installed in sockets on the 
board and may be easily inserted or removed where 
required. 

 

Failsafe Receivers 

- The receivers employed in this model 

include a fail-safe feature which guarantees a high output 
state when the inputs are left open or floating. 

 

Internal Diagnostic Capabilities

 - Loopback controls for 

communication link fault isolation are included.  Break, 
parity, overrun, and framing error simulation are also 
possible. 

 

Compatible with Industry Standard UARTs 

- The UART of 

this IOS module is compatible with the industry standard 
ST16C554/654, ST68C554/654, and TL16C544.  
Additionally, this device can operate in a 16C450 UART 
family software compatible mode.  The transmit and receive 
channels are double-buffered in this mode.  Hold and shift 
registers eliminate the need for precise synchronization 
between the host CPU and the serial data. 

 

Software Flow Control

 - One or two sequential receive 

data characters are compared to a programmed Xon or Xoff 
character value.  Data transmission can be suspended or 
resumed via software flow control. 

 

Sleep Mode

 -The UART can be set via register control to a 

special sleep mode to reduce power consumption when the 
chip is not being used. 

 

Conduction Cooled Module

 

- I/O modules employ 

advanced thermal technologies. A thermal pad and module 
cover wicks heat away from the module and transfers the 
energy to a heat spreading friction plate. Heat moves to the 
enclosure walls where it is dissipated by the external cooling 
fins. 

 
I/O SERVER MODULE SOFTWARE LIBRARY 
 
IOS MODULE Win32 DRIVER SOFTWARE 

 

Acromag provides a software product (sold separately) to 

facilitate the development of Windows Embedded Standard 
applications interfacing with I/O Server Modules installed on 
Acromag Industrial I/O Server systems.  This software (Model 
IOSSW-DEV-WIN) consists of a low-level driver and Windows 32 
Dynamic Link Libraries (DLLS) that are compatible with a number 
of programming environments including Visual C++, Visual 
Basic.NET, Borland C++ Builder and others.  The DLL functions 
provide a high-level interface to the IOS carriers and modules 
eliminating the need to perform low-level reads/writes of 
registers, and the writing of interrupt handlers. 

 
 
 

IOS MODULE LINUX SOFTWARE 

 

Acromag provides a software product (sold separately) 

consisting of Linux  software. This software (Model IOSSW-API-
LNX) is composed of Linux libraries designed to support 
applications accessing I/O Server Modules installed on Acromag 
Industrial I/O Server systems The software is implemented as a 
library of “C” functions which link with existing user code 

 

2.0   PREPARATION FOR USE 

 

UNPACKING AND INSPECTION 

 

Upon receipt of this product, inspect the shipping carton for 

evidence of mishandling during transit.   If the shipping carton is 
badly damaged or water stained, request that the carrier's agent 
be present when the carton is opened.   If the carrier's agent is 
absent when the carton is opened and the contents of the carton 
are damaged, keep the carton and packing material for the 
agent's inspection. 

 

For repairs to a product damaged in shipment, refer to the 
Acromag Service Policy to obtain return instructions.   It is 
suggested that salvageable shipping cartons and packing 
material be saved for future use in the event the product must be  

 
This board is physically protected with 
packing material and electrically 
protected with an anti static bag during 
shipment.  However, it is recommended 
that the board be visually inspected for 
evidence of mishandling prior to 
applying power. 
 
The board utilizes static sensitive 

components and should only be handled at a static-safe 
workstation. 

 
 
BOARD CONFIGURATION 

 

Power should be removed from the board when installing IOS 

modules, cables, termination panels, and field wiring.  Refer to  
the following discussion for configuration and assembly 
instructions.  Model IOS-521 communication boards have no 
hardware jumpers or switches to configure. 
 

CONNECTORS 

 
Connectors of the IOS-521 module consist of one IOS 

module field I/O connector, and one IOS module logic connector.  
These interface connectors are discussed in the following 
sections. 

 
IOS Field I/O Connector (P2) 

 

P2 provides the field I/O interface connections for mating IOS 

modules to the carrier board.  P2 is a 50-pin female receptacle 
header (AMP 173279-3 or equivalent) which mates to the male 
connector of the carrier board (AMP 173280-3 or equivalent).  
This provides excellent connection integrity and utilizes gold-
plating in the mating area.  The field and logic side connectors 
are keyed to avoid incorrect assembly. 

 

 

Summary of Contents for IOS-521 Series

Page 1: ...G INCORPORATED Tel 248 295 0310 30765 South Wixom Road Fax 248 624 9234 P O BOX 437 Wixom MI 48393 7037 U S A solutions acromag com Copyright 2009 2011 Acromag Inc Printed in the USA Data and specific...

Page 2: ...pecially important where economic property loss or human life is involved It is important that the user employ satisfactory overall system design It is agreed between the Buyer and Acromag that this i...

Page 3: ...ver Modules installed on Acromag Industrial I O Server systems This software Model IOSSW DEV WIN consists of a low level driver and Windows 32 Dynamic Link Libraries DLLS that are compatible with a nu...

Page 4: ...nd which is typically common to safety chassis ground when mounted on a carrier board and inserted in a backplane As such be careful not to attach signal ground to safety ground via any device connect...

Page 5: ...1 R W Xoff 2 High Byte BF Hex 0E 11 1F Not Driven1 Port B Registers Organized as Port A3 10 1E 21 2F Not Driven1 Port C Registers Organized as Port A3 20 2E 31 3F Not Driven1 Port D Registers Organize...

Page 6: ...lag in the LSR register will be set to a logic 1 when at least one FIFO location is available DLL DLM Divisor Latch Registers Ports A H R W The Divisor Latch Registers form the divisor used by the int...

Page 7: ...ansitions from a logic 0 to a logic 1 RTS is not output by this module Instead RTS is used to enable the transmitter of the port This interrupt should always be disabled 71 0 Disable CTS Interrupt 1 E...

Page 8: ...register control the format of the data character as follows Line Control Register LCR Bit FUNCTION PROGRAMMING 1 0 Word Length Sel 0 0 5 Data Bits 0 1 6 Data Bits 1 0 7 Data Bits 1 1 8 Data Bits 2 S...

Page 9: ...ne The crystal frequency is unchanged 1 Divide by four After the crystal frequency is divided by 16 it is further divided by 4 see Table 3 2 Notes Modem Control Register 1 MCR Bit 4 provides a local l...

Page 10: ...f the FIFO Line Status Register continued LSR Bit FUNCTION PROGRAMMING 4 Break Interrupt BI 0 No Break 1 Break the received data input has been held in the space logic 0 state for more then a full wor...

Page 11: ...1 IOS module The EXAR UART maintains compatibility with the industry standard 16C554 654 and 68C554 654 UARTs and provides new features to enhance serial communication operation The new features provi...

Page 12: ...nformation includes unique information required for the module The IOS 521 ID Space does not contain any variable e g unique calibration information ID Space bytes are addressed using only the even ad...

Page 13: ...ive FIFO s simply hold characters and the Line Status Register must be read to determine the channel status FIFO Polled Mode Resetting all Interrupt Enable Register IER bits to 0 with FIFO Control Reg...

Page 14: ...H then port A in a last serviced last out fashion Priority continues to shift in the same fashion if Port B or Port C was the last interrupt serviced This is useful in preventing continuous interrupt...

Page 15: ...s the first step to enable the receiver line status interrupt Note bit 3 of the MCR must also be set to logic 1 to enable interrupts The line status interrupt is used to signal error cases such as par...

Page 16: ...gic 1 by a negative voltage The line receivers convert these signals to the conventional TTL level associations EIA TIA 422B BINARY 0 SPACE OFF BINARY 1 MARK ON SIGNAL A to B to Positive Differential...

Page 17: ...serted An Asterisk is used to indicate an active low signal IOS 521 OPERATION Connection to each serial port is provided through connector P2 refer to Table 2 1 These pins are tied to the inputs and o...

Page 18: ...ake adequate measures UART EXAR XR16C654 RS422 RS485 PORTS Channel Configuration Eight independent non isolated EIA TIA 422B serial ports with a common signal return connection Data Rate 921 6K bits s...

Page 19: ...COMMON GND IOS 521 BLOCK DIAGRAM T T T B R R R R I O RS 422B INTERFACE RxD RS 422 485 DRIVERS RECEIVERS RxD TxD PORT I O CONTROL BUS ADDRESS BUS 5V CONTROL LOGIC SUPPLY FILTERING NOTE TERMINATION RES...

Page 20: ...TE OF THE TxD RxD DATA PAIRS ARE HIGH ON TxD RxD THIS CORRESPONDS TO A MARK 1 ON THE DATA LINE NOTES CONCERNING RESISTOR PLACEMENT AND REMOVAL FOR RT AND RB 4 THE TxD LINE SOURCED FROMA PORT CAN BE PE...

Page 21: ...PORT C RxD H TERMINATION TxD C TERMINATION RxD C TERMINATION 120 OHM 120 OHM 120 OHM PORT E TxD E TERMINATION PORT H PORT E RxD E TERMINATION TxD H TERMINATION 120 OHM 120 OHM 120 OHM PORT B RxD B TER...

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