December 2001 Machine Operating Panel 3 – 87
3.17 Machine Operating Panel
For machines with up to four axes, HEIDENHAIN offers the MB 420 machine
operating panel. It is installed below the operating panel. There are two
versions of the MB 420 available, one with a standard set of keys and the other
with a set of keys to be selected and placed by the machine tool builder. An
assortment of approx. 40 placeable keys is supplied with the latter version.
On the underside of the machine operating panel are two terminal strips
bearing the PLC inputs I151 and I152 as well as the PLC outputs O0 to O7.
Assignment of PLC inputs to the keys of the MB 420:
X46: PLC inputs and
outputs
PLC inputs I128 to I152 and the PLC outputs O0 to O7 are located at X46 of
the machine operating panel. The reference potential (PLC) for outputs O0 to
O7 is connected to pins 34 and 35.
Pin layout of logic unit, connecting cable, and machine operating panel:
I
136
I
135
I
134
I
137
I
128
I
148
I
133
I
149
I
129
I
130
I
131
I
132
I
138
I
143
I
145
I
139
I
150
I
140
I
141
I
142
I
146
I
147
I
144
Warning
PLC inputs I128 to I152 must be driven only with the power supply from
pins 36 and 37, because this power supply is internally protected (PLC
power supply from X44 connection 2).