Analog Outputs; Wiring The Dual Dac; Wiring The Serial Dac; Serial Communications - Watlow CLS200 User Manual

CLS200 Series User's Guide
Chapter 2: Installation

Analog Outputs

Analog outputs can be provided by using a Dual DAC or Serial DAC module to convert the open
collector outputs from the controller. Use multicolored stranded shielded cable for analog outputs.
Analog outputs generally use a twisted pair wiring. The following sections describe the Dual DAC
and Serial DAC modules.

Wiring the Dual DAC

A Dual DAC module includes two identical circuits. Each can convert a distributed zero-cross (DZC)
signal from the controller to a voltage or current signal. Watlow strongly recommends using a power
supply separate from the controller supply to power the Dual DAC. Using a separate power supply
isolates the controller's digital logic circuits and analog measurement circuits from the frequently
noisy devices that take the analog signal from the Dual DAC.
Several Dual DAC modules may be powered by one power supply. Consult the Dual DAC's manual
for power requirements. Also note that the Dual DAC does not carry the same industry approvals as
the Serial DAC.

Wiring the Serial DAC

The Serial DAC provides a robust analog output signal. The module converts the proprietary Serial
DAC signal from the controller's open collector output in conjunction with the clock signal to an
analog current or voltage. The Serial DAC is user-configurable for voltage or current output.
The Serial DAC optically isolates the controller's control output from the load. When a single
Serial DAC is used, it may be powered by the 5VDC found on the TB50, or by an external supply
referenced to the controller's power supply. When using multiple Serial DACs, the controller cannot
provide sufficient current; use the 5VDC output from the CLS200 power supply.

Serial Communications

The CLS200 series controllers are factory-configured for EIA/TIA-232 communications unless
otherwise specified when purchased. However, the communications are jumper-selectable, so you
can switch between EIA/TIA-232 and EIA/TIA-485. See Changing Communications on page 153.

EIA/TIA-232 Interface

EIA/TIA-232 provides communication to the serial port of a compatible computer. It is used for single
controller installations where the cable length does not exceed 50 feet (15.2 m).
The EIA/TIA-232 interface is a standard three-wire interface. See the table below for connection
information.
If you are using EIA/TIA-232 communications with grounded thermocouples, use an optical isolator
between the controller and the computer to prevent ground loops.
Table 2.10 shows EIA/TIA-232 connections for 25-pin and 9-pin connectors.
EIA/TIA-232 may be used to connect a computer through a 232/485 converter, to an EIA/TIA-485
communications network with up to 32 CLS200 controllers.
44