DE2656981C3 - Control for the current-dependent dosing of bath additives - Google Patents

Description

The invention relates to a control for the current-dependent metering of bath additives, in particular of electrolyte additives for the common bath of several electroplating units, in which the Shunt voltages of each aggregate current-dependent quantities continuously from an ampere-hour counter and control device are added up, with pulses from this device controlling the downstream Doser takes place.

In electroplating technology in particular, the reliable dosing of liquid bath additives is one of the determining factors the surface quality of the goods and lowers the chemical costs. Because of the different batches will be often several electroplating units, in particular electroplating drums, in a common bath treated. The constant loss of electrolyte must be automatically compensated for using controlled dosing devices will.

A converter parallel connection of a metering / ampere-hour combination with a single power supply is known several electroplating units with a common electrolyte bath, with each rectifier A direct current converter is connected downstream with a shunt. The respective electroplating current passed through the converter. The output alternating voltages are connected by an known summing device added up by an ampere-hour counter and control device. Impulse of this device control the downstream batch feeder.

Since the individual electroplating systems have shunts of different sizes (shunt resistors), requires such a plant DC converters of various sizes. These DC converters that

is manufactured according to its area of application are relatively expensive due to the only possible small series production. Likewise, that requires known total add-on device a considerable cost input.

The object of the invention is to propose a control of the type mentioned at the outset, which requires lower costs with the same reliability and higher measurement accuracy.
To solve this problem of the invention, such a control is characterized in that each shunt voltage is applied via a channel assigned to each unit to a voltage-frequency converter with a frequency divider that adjusts the ratio of shunt size / frequency, and the individual output frequencies of these converters are sampled and scanned by a downstream multiplexer are added up in the downstream counter.

According to a preferred embodiment of this control, the samples are scanned by the multiplexer Output frequencies are added up in a downstream preset counter which, after reaching a a certain number of ampere-hours sends a pulse to the downstream dosing unit. To prevent Short circuits and any disturbance variables that may occur are assigned to the individual units Channels separated via an OPTO coupler.

The invention brings a more economical electronic control of the current-dependent metering of Bath additives that do without the costly direct current converters and summing accessories can be. The relatively small changes in voltage are relatively large changes in frequency across the converter assigned, which are recorded in a simple manner by sinem ampere-hour counter and control device

so let. The possibility of equipping frequency converters with adjustable frequency dividers in a known manner, enables the uniform adjustment of the same ratio of shunt size to frequency at each Electroplating unit. The number of channels the

π corresponds to the number of aggregates, as well as the shunt sizes can be chosen arbitrarily.

1 sheet of drawings

Claims (3)

Patent claims: 1. Control for the current-dependent dosing of bath additives, in particular of electrolyte additives for the common bath of several electroplating units, in which the current-dependent values of the shunt voltages of each unit are continuously added up by an ampere-hour meter and control device, with the control of the downstream dosing device via pulses from this device takes place, characterized in that each shunt voltage is applied via a channel (1 ... n) assigned to each unit to a voltage-frequency converter (1) with a frequency divider equalizing the ratio of shunt size / frequency, and the individual output frequencies of these converters via a Multiplexer (2) are scanned and added up in the downstream counter (3). Control according to Claim 1, characterized in that those scanned by the multiplexer (3) Output frequencies are added in a downstream preset counter (3), which is after When a certain number of ampere-hours is reached, an impulse is sent to the downstream dosing unit. 3. Control according to claim 1, characterized in that the channels (1 ... n) assigned to the individual units are separated from one another via an OPTO coupler to prevent short circuits and any disturbance variables that may occur.