VDH MC 885-SDHL Manual

VDH doc: 180146
Software: 110365_MC 885 SDHL
* Working principle
The MC 885 SDHL is a thermostat for controlling >on/off= burners with >high/low= burner control by means of
relay contacts. In addition to this, modulating control is also possible. The thermostat supports 2 mode=s
(mode S and mode D), each having their own setpoint. It is possible to alternate between the mode=s using
a digital input. When applied to a spray booth regulation function, mode S can be used for spraying and
mode D for drying. These modes can be optionally be used in other applications; for example, mode S for
night and mode D for day.
The working principle of the controller is determined by the parameter settings. The controller can control
using 1 or 2 mode=s(/setpoints), with 1 or 2 sensors, where appropriate depending on the current mode (S
or D).
The basic regulation function supports the control functions >burner on=, >burner low= and >burner high= as
shown in the functional flow figure. One of these control functions can be set for each relay. If a burner has
to be controlled with a change-over relay contact >burner high/low=, control function >burner high= can be
used for this on RY2 or RY3.
The measurement and control range are both -50 to 300 C, with a readout per 1 C. The control range can
be reduced using the parameter setting. The top display normally gives the measured room temperature
and the bottom display gives the active setpoint.
In addition to the basic regulation function, the controller also has a minimum and maximum alarm detection
and a maximum limit. The temperature and mode=s at which the alarms and limit should work can be set via
the parameters. The desired action when an alarm or limit is triggered can also be set.
If the controller detects a sensor failure, the regulation function stops, an error message appears in the
display and the alarm relay function becomes active.
The controller also has a configurable analogue output, power-up control delay, buzzer, operate/parameter
passwords and an optional RS485 network connection (for ALFANET or Modbus).
The working principle of these functions is described later in this manual.
MC 885-SDHL
Spray/Dry High/Low Thermostat
Version: v1.0
File: Do180146.wpd
Date: 05-02-2018
Range: -50/+300C per 1C