Inputs and Outputs

The CR15+ has a total of 30 outputs for control of max. 15 heating / cooling circuits. The outputs are able to switch 24VDC, 24 VDC or 230VAC in a pulse package mode. The input sensors can be Pt100, Fe-CuNi or NiCr-Ni. The supply voltage may be selected of 24VDC, 24VAC or 230VAC. The CR15+ has a standard RS485 interface to an external visualisation for control and monitoring. Optional RS232 or RS422 interfaces are available.

Operating and Display Unit

The display of parameters and the setting of parameters and operation modes is performed via the operating and display unit. There are two basic modes:

• Display mode: As requested by the user all setpoint values, process values, control deviations, output values or current values of all zones are displayed simultaneuosly. An external optional current sensing module is required for heating current monitoring.
• Input mode: This mode allows to enter all values required for control operation. All parameters are described in text format. A three level password protection prevents unauthorized parameter entry. For a clearly arranged display this mode will show only the number of the selected channel and the corresponding setpoint and process value.

Alarms

All control circuits are monitored for under- and over-temperature. In case of alarm condition the referring isolated relay contacts change status. The alarms are indicated summary. The alarm code is displayed in the window of the corresponding channel. This enables to determine the type of error (over- / under-temperature, broken or shorted sensor) and the location of error (zone 1, 2 or..) immediately.

The integrated monitoring of the thermocouples prevents none plausible temperature behaviour like increasing temperature without any heating or no temperature increasing at max. heating current.

Selfoptimizing Mode

The CR15+ includes a selfoptimizing mode based on FUZZY-logic. Depending on the application different methods are available. For sluggish control systems (e.g. extruders) the tuning method "start-up trial is used to determine the heating parameters and the tuning method "sink to determine the cooling parameters. The tuning method "swing trial is used for fast control systems (e.g. hot-channel applications).

Control Structure

• The controller uses for internal calculation a temperature resolution of ¼ °C. The display is reduced to 1° C resolution.
• The minimum calculation cycle per channel is 10 msec (= of 1% regulation rate).
• The scan time for all 15 channels is 1 sec.
• The control structure for all heating circuits is similar to a PID control with start up ramp.
• Four independent setpoint programs can be stored for each channel, e.g. stand by temperature or new temperature profiles. The programs stay in memory even without power supply. A 24 VDC PLC-parallel input allows external selection of setpoint programs.
• The parameter operation level allows process and user required presettings, e.g. activating ramp functions, selecting °C or °F or the modification of the PID-structure.
• For each channel the CR15+ may be switched to a power mode (manual or preselected output), this enables a mixed operation of the channels.