Akytec TRM138, User Manual, Page: 4 / 40

Overview
akYtec GmbH · Vahrenwalder Str. 269 A · 30179 Hannover · Germany Tel.: +49 (0) 511 16 59 672-0 · www.akytec.de
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1 Overview
This guide describes the functions, system configuration, operating instructions, pro-
gramming and troubleshooting of the 8-channel on-off controller TRM138 (hereinafter
referred to as TRM138, device, or controller).
1.1 Functions
The 8-channel on-off controller TRM138 is intended for automatic control systems in vari-
ous technological processes in different areas of industry, agriculture and utilities.
The controller provides following basic functions:

measuring of input values and transformation of the input signal according to the
sensor type

displaying the measured values and configuration parameters on 4-digit LED dis-
plays

digital filtering of the input signal (EMI-interference protection)

signal correction

creating an alarm signal in case of sensor failure, displaying the cause of the fail-
ure, using the outputs for alarm signals

creating control signals for actuating devices according to configuration parame-
ters

manual control, creating control signals using the function keys
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full control over PC using RS485 interface
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operating with akYtec, Modbus-RTU and Modbus-ASCII protocols in a Slave
mode

saving the set programmable parameters to non-volatile memory in case of pow-
er outage

configuration via PC or using the function keys.
1.2 RS485 network
The TRM138 uses the common standard RS485 for data exchange.
Serial interface RS485 enables communication via two-wired line in half-duplex mode.
The module supports the Modbus RTU, Modbus ASCII and akYtec protocols with auto-
matic protocol detection.
The network consists of a Master device and can contain up to 32 Slave devices. Maxi-
mum length is 1200 m. The number of Slave devices and network length can be in-
creased using RS485 interface repeater.
Devices are connected to a network according to linear (bus) topology. It means that the
line goes from the first device to the second one, from the second one to the third one,
etc. Star connection and spur lines are not allowed.
Line reflections always occur at each of the 2 ends of the bus (the first and the last node).
The higher the data transmission rate, the stronger they are. A terminating resistor is
needed to minimize reflections. Line termination may be a 150 ohms value (0.5 W) resis-
tor.
The TRM138 can be used as a Slave device only. Master device can be PLC, computer
with SCADA software or control panel.