Doc: I437GB04_16.docx 09/03/2016
p. 7 / 37
Communication channels
The ATL900 has an integrated RS-485 communication port named COM1.
Up to two additional communication modules, named COM2 and COM3, can be connected.
The communication settings menu has three parameter sections (n=1 ... 3) for setting the communication ports.
The communication channels are completely independently from the hardware point of view (physical interface type) and from the point of view of the communication protocol.
The communication channels may operate at the same time.
By activating the Gateway function, it is possible to have an ATL900 equipped with an Ethernet port and the basic RS-485 port which works as a ‘bridge’ towards the other
devices provided with the RS-485 port only, so obtain a saving (one Ethernet access point only). In this network, the ATL900 provided with Ethernet port will have the
Gateway
function set to ON for both communication channels (COM1, COM2) while the other devices will be normally configured with
Gateway
= OFF.
Inputs, outputs, internal variables, counters, analog inputs
The inputs and outputs are identified by a code and a sequential number. For example, the digital inputs are named INPx, where x is the input number. Similarly, the digital
outputs are named OUTx.
The input/output numbering is based simply on the assembly position of the expansion modules with a sequential numbering from the top down.
Up to 6 analog inputs (AINx) can be managed coming for external sensors (temperature measurements, consumption, pressure, flow rate etc.). The value read by the analog
inputs may be converted into any engineering unit shown on the display and made available on the communication bus. The quantities read by the analog inputs are shown on
the specific page. Limit thresholds (LIMx) may be applied to each one, which in turn can be connected to an inner or outer outputs, or inserted in a PLC logical function.
The expansion I/O numbering starts from the last I/O fitted on the base unit. For example, for digital inputs, INP1…INP12 on the basic unit and thus the first digital input on the
expansion modules will be named INP13. The I/O numbering is shown in the following table:
CODE
DESCRIPTION
BASIC
EXP
INPx
Digital inputs
1…12
13…20
OUTx
Digital outputs
1…11
12…20
COMx
Communication ports
1
2...3
AINx
Analog inputs
-
1…6
AOUx
Analog outputs
-
1…6
RALx
Remote relays for alarms/states
-
1…24
Like the inputs/outputs, there are internal variables (bit) which may be associated to the outputs or combined. For example, limit thresholds can be applied to the measurements
performed by the system (voltage, current etc.). In this case, the internal variable, named LIMx, will be activated when the measurement is beyond the limits defined by the user
by means of the respective setting menu.
Furthermore, up to 8 counters (CNT1…CNT8) which can count pulses come from the outside (thus from INPx inputs) or the number of times for which a given condition
occurred. For example, by defining a LIMx threshold as counting source it will be possible to count how many times a measurement exceeds a given value.
The following table shows all the internal variables managed by the ATL900 with their range (number of variables per type).
CODE
DESCRIPTION
RANGE
LIMx
Limit thresholds on measurements
1…16
REMx
Variables controlled remotely
1…16
UAx
User alarms
1…8
CNTx
Programmable counters
1…8
PLCx
PLC logic variables
1…32
TIMx
Timer
1…8
Limit thresholds (LIMx)
The LIMn limit thresholds are internal variables the state of which depends on a measurement of those performed by the system going beyond the limits defined by the user, e.g.
total active power higher than 25kW).
To speed up setting considering that each threshold can span across an extremely wide range, each threshold can be set to a base value + a multiplying coefficient
(e.g.: 25 x 1k = 25000).
Two thresholds are available for each LIM (upper than lower). The upper threshold must always be set to a value higher than the lower value.
The meaning of the thresholds depends on the following functions:
Min function
: with the Min function the lower threshold is the tripping threshold and the upper threshold is the resetting threshold. The threshold is activated after the set delay
when the value of the selected measurement is under the lower limit. Reset is activated after the set delay when the value of the measurement is higher than the upper threshold.
Max function
: with the Max function the upper threshold is the tripping threshold and the lower threshold is the resetting threshold. The threshold is activated after the set delay
when the value of the selected measurement is higher than the upper limit. Reset is activated after the set delay when the value of the measurement is lower than the lower
threshold.
Min+Max function:
with the Min+Max function both the upper and the lower thresholds are intervention thresholds. The threshold is activated after the respective delays when the
value of the selected measurement is either lower than the lower limit or higher than the upper limit. Resetting is immediate as soon as the value returns within the limits.
Tripping may mean energising or de-energising the LIMn limit according to the setting.
If the LIMn limit is set with memory, manual resetting is possible using the specific control in the command menu.
See the M15 settings menu.
Upper threshold
Lower threshold
Measurement type
Limit variable state
Function
Measurement value
Threshold delay
