Introduction
This note describes a simple way of connecting Omron CPM2C-CIF21 communication unit to E5_N temperature controllers to read PV and Status and write the Setpoint. For the purpose of this example we assume that there is 1 temperature controller with node numbers 1. Details of the connections and dip switch settings can be found W356-E1-05. By default communications setting is 9600,7,E,2. Set the terminating resistor to on at the CIF21 end and wire a 120c resistor as per manual with the temperature controller.
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This diagram shows how the data memories have to be configured. The shared area section indicates the number of units attached, their communications protocol and the pointers to read/write variable type areas for each unit.
These parameters can be fixed or under total program control. The simplest form is simply to have as many of the parameters as fixed.
Although in principle it is possible to hold a lot of the configuration parameters in the PLC in practise it is best if configuration is performed via Thermotools software or E5ZN-SDL unit.
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| The Setup above will read SP, PV and Status on Unit 1 and write Setpoint on every CIF21 sample once the run/stop bit has been set to 1. In order to ensure that writing parameters is enabled the operation command (00 01 Enable Communications Writing) may have to be used to activate writing of Setpoints. Reading/Writing to additional units can be done in a similar manner by enabling additional unit numbers on the Compoway F/Link. |
